Apparatus for removing fines in bucket loaders



y 1947- A. G. GRANATH ET AL 2,424,272

APPARATUS FOR REMOVING FINES IN BUCKET LOADERS I Filed Aug. 25, 1944 s Sheets-Sheet 1- 54' Eg I f6 4/ ZNMENZU IfS flzel G Granalh Julius J Gruen eld July 1947- A. e. GRANATH ET AL APPARATUS FOR REMOVING FINES IN BUCKET LOADERS Filed Aug. 25, 1944 s, Sheets-Sheet 2 Arr/EN U 5 flrel G Graml'iz r Julzzw J. Gruerzfelai E W July 22, 1947.

A. G..GRANATH El AL APPARATUS FOR REMOVING FINES IN BUCKET LOADERS Filed Aug. 25, 1944 3 Sheets-Sheet 3 N E; U JZxeZ G. Grana Julz'zgs J Gruerzfela, 37 V ZL-vs Patented July 22, 1947 APPARATUS FOR, REMOVING FINES IN BUCKET LOADERS Axel G. Granath and Julius J. Gruenfeld, Chito Herbert S. Simpson,

cago, Ill., assignors Evanston, Ill.

Application August 25, 1944, Serial No. 551,170

16 Claims.

In the mixing and mulling treatments of granular materials, such as foundry sands and the like, used foundry sand becomes mixed with minute parts of burned clay and broken sand grains, which are termed fines and when allowed to accumulate results in the formation of defective sand molds in which the sand is not properly vented or in which there is a loss of permeability. It is consequently desirable in the treatment of foundry sand and the like to remove the fines to obviate loss of permeability.

It has been customary in the past to remove fines from foundry sand and the like, by a method requiring a separate screening unit over which the sand is first passed and is subjected to air currents to exhaust the fines from the sand before the sand is treated or prepared for molding purposes. Another method used is one in which the sand is first delivered into a treating machine, such as a mixer and muller, from which the fines are exhausted direct, by using a very high volume of air which is passed over the top of the material while it is being treated. The first of these methods requires considerably more equipment and, therefore, a greater outlay is necessary to provide every mixer with a separate screening unit. In the second method, referred to, a greater volume of air is required when fines are exhausted direct from the mixer.

Neither of the two fine removal methods referred to are adaptable for use in the average small foundry for which a demand has been created for a fines control unit of inexpensive and efficient construction.

This invention relates to an improved and simplified, inexpensive and efiective bucket loader mechanism for use in loading foundry sand mixers and mullers or other granular material treating machines, said loading mechanism being of the bucket type and including a screening and air suction loading bucket. A current of air is suctioned directly through the entering material stream and out of the bucket thereby removing the fines from the material as it enters the bucket, allowing the fine free material to fill the bucket ready for discharge into a material treating machine, such as a foundry sand mixer and muller used in combination with the improved air exhaust loader of this invention.

An object of the invention, is the provision of a very simple and compact combined bucket loading, screening, and fine exhausting unit, for use with material treating machines.

It is an object of this invention to provide a material treating machine with a material loader including an air controlled loading bucket adaptable for removing fines from the material as it enters the bucket for subsequent feeding into the machine substantially free from fines, permitting the fine free material to be treated and bonded in the machine and then reused. for the making of molds or the like without loss of permeability therein.

It is also an object of this invention to provide an apparatus for feeding materials to a treating machine by subjecting the material entering the apparatus to a dry type exhaust treatment, for effecting removing fines from the material thereby obviating loss of permeability in articles formed from the reclaimed material.

It is a further object of the invention to provide a material bucket loader mechanism which incorporates in its design fines removal produced by suctioning air through the material while entering the loader.

It is furthermore an object of the invention to provide an improved apparatus for screening and cleaning foundry sand and similar materials of coarse foreign matter and fines while entering a loader, which apparatus is economical, clean and efiective.

A feature of the invention is the provision of a loading mechanism including a bucket provided with a hoist switch controlled electric vibrator for operating a screen permitting the removal of coarse matter and the entrance of the fines material into the bucket and the simultaneous treatment thereof to air exhaust currents for the efiective removal of fines from the material prior to the treatment of the material for foundry mold making purposes or the like.

Another feature of the invention is the provision of a spent foundry sand feeder or loader having a vibrator controlled screen governed by a limit switch for starting the operation of the screen when the loader bucket is in a receiving position, to cause a more finely diffused stream of sand to enter the bucket to be subjected to air exhaust currents, whereby the major portion of the fines are removed from the sand before it is delivered to a sand mixer, muller and bonding machine.

Another object of the invention is the provision of a bucket loading unit including a bucket loader provided with a screen operable by a vibrator having a control switch which also stops the downward travel of the bucket loader so that as the loader comes to rest the vibrator starts vibration of the screen.

Other and further important objects of the will be apparent from the disclosures the accompanying drawinvention in the specification and ings.

The invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described.

On the drawings:

Figure 1 is a side elevation of a material treating system including an improved bucket loading screening and fine exhaust unit embodying the principles of this invention and adaptable for expeditiously and economically carrying out the method of fine removal during the loading and feeding of material to a treating station;

Figure 2 is a front elevational view of the system and the loading unit forming a part thereof;

Figure 3 is an enlarged fragmentary vertical detail section taken on line Ill-III of Figure 2 to illustrate the relationship of the loading bucket with respect to the screen and vibrator and the contact between the bucket and the air exhaust box;

Figure 4 is a fragmentary horizontal detail view, taken on line IV-IV of Figure 3;

Figure 5 is a fragmentary vertical sectional view taken on line V-V of Figure 4;

Figure 6 is a fragmentary vertical detail section taken on line VI-VI of Figure 5 showing the loading bucket in its lowered position and operating the lower limit switch; and

Figure 7 is a schematic wiring diagram for the control and operation of the loading bucket and the vibrator for operating the bucket screen.

As shown on the drawings:

The present invention relates to an apparatus for removing coarse foreign elements and fines from spent granular materials, such as used foundry sand and the like, said method and apparatus being adaptable for use in small foundries at nominal cost for the feeding or loading of the materials and for the removal of coarse foreign matter and fines in the loading container used for delivering the material to a treating or conditioning machine such as a foundry sand mixer and muller.

The improved loader is designed and constructed to produce an increased efficiency by improving the method of delivering spent foundry sand and similar materials to a treating machine by causing simultaneous screening and suction fines removal in the delivery bucket while being loaded.

As illustrated in Figures 1 and 2, the improved screening and fines removal loading unit, is shown in coacting relationship with a foundry sand mixing, mulling and bonding machine hereinafter referred to as a mixer. The material receiving and treating mixer may be of any selected type such for example as the mixer shown and claimed in the-pending application for patent of Alfred C. Christensen, filed May 10, 1944, United States Serial No. 534,912. The mixer shown, briefly comprises a base or pedestal l supporting a driving motor 2 for driving a gear mechanism within the base. The operation of the motor 2 and the mixer is governed by means of an electric control box 3 having a start and stop push button switch box 4 connected therewith for starting and stopping the operation of the mixer.

Supported on the base I, is a crib 5 within which the motor driven mixing, plowing and mulling mechanisms are mounted. Removably engaged on the crib 5 is a cover or hood 6 provided with a material receiving or loading chute '1 having a receiving opening or loading port 8 through which screened sand, from which the fines have been removed, is adapted to be fed-into the mixer crib 5 for treatment.

Mounted adjacent the mixer is an improved material loading machine unit by means of which batch feeding of a material, such as spent foundry sand is adapted to be accomplished. The loader unit comprises a vertical framework consisting of two channel uprights 9 the lower ends of which are secured to the floor by suitable angle iron feet lfl. The framework uprights 9 are connected by transverse frame members to form a rigid structure.

Rigidly secured on the back of the upright framework is a rear or auxiliary framework H which is disposed between the loader framework and the mixer, as clearly shown in Figure 1. Mounted on one side of the auxiliary framework H is a control board or panel l2 on which the mixer control box 3 and the mixer push button switch box 4 are mounted. Also mounted on the panel I! above the control boxes 3 and 4 is a standard type hoist control motor reversing unit I3 having connected therewith a three push button switch control box l4 for governing the raising, stopping and lowering of the loading bucket.

Mounted on the control panel l2 above the control units l3 and I4 is an air exhaust control unit or operating box IE to which an air control start and stop two push button switch box I6 is connected. The air exhaust push button switch box IE is also mounted on the panel [2 as shown in Figure 1.

One of the main features of this invention is to provide a material feeding or loading unit, for mixers and the like, by which batch bucket loading, screening and fines exhausting may be efficiently and economically accomplished.

The loading unit consists of a bath type feeder mechanism including a container or bucket comprising a main body portion I! having a material receiving opening l8 in an inclined top wall thereof. Formed upon the top and across the rear of the bucket main body portion l! is a material discharge or feeding spout or chute l9 having an air exhaust opening or port 20 in the upper portion of the back wall thereof. The upper end of the bucket discharge chute I9 is open and is provided with a flop gate 2| hingedly connected to the top edge of the front wall of the bucket chute 19 as illustrated in Figure 3.

The bucket receiving opening [8 is covered by means of a screening unit comprising a screen frame or mounting 22 which is disposed in an inclined plane on the open top of the bucket I! to which the screen mounting is secured, as shown in Figure 3. The screen mounting carries a resiliently mounted screen 23 which is of the vibratory type. The spent or inert foundry sand or other material, which is to be reclaimed or treated in the mixer, is loaded or delivered into the bucket H, by shovelfuls or may be delivered in batches by means of wheel barrels or from dump cars or the like permitting the material to drop into contact with the screen 23. The finer material is permitted to sift into the bucket while the larger or coarser portions of the material, such as scrap nails, gaggers and the like are held back by the vibrating screen and are permitted to slide downwardly thereover to be discharged and conveyed away by any suitable means,

It will thus be noted that the screened sand and the fines mixed therewith pass into the bucket in a finely diffused stream by means of the action of the vibrating screen 23. The screen 23 is connected for operation by a selected standard type of electric vibrator 24, by two feed wires 25 and 26 disposed within a conduit 27 leading from the vibrator 2 3' into the top of a vibrator start and stop switch control unit disposed within a switch housing or case 28. The switch case 28 is provided with apertured flanges permitting the same to be bolted to one side of the bucket i i.

The two wires 25 and 26 pass into the vibrator control switch case 28. The wire 25 is connected to a switch contact spring 29 while the wire 28 is connected to a switch contact spring 38. The contact springs 29 and 39 are mounted in the case 28 (Figures and 6) and are respectively adapted to be carried by the movement of the bucket into and out of contact with two stationary vibrator control contacts 31 and 32 as the bucket moves into its lowermost or loading position and as it rises to leave said position for de livering a charge of the material to the mixer.

The vibrator control contacts 3! and 32 are supported on an arm 33 forming an extension of an adjustable bracket plate 3% having adjusting slots 35 formed therein for the reception of clamping bolts 35 for holding the bracket plate 34 bolted in place. The vibrator control contacts 3| and 32 may be raised or lowered by adjusting the supporting plate 3t by means of the slots 35 when the bolts 33 are loosened. Respectively connected with the vibrator control contacts 3i and 32 are wires 3'. and 38 which respectively connect up with vibrator control terminals 39 and 49 provided in a bucket lowering control switch box 4| mounted on the lower portion of one of the framework uprights Q. Also provided in the control switch box 3! is a vibrator control terminal 42.

Provided in the lowering control switch box are two motor control terminals :93 and M. A combination vibrator and bucket lowering auxiliary control switch 45 is mounted in the box 4! and is operable by means of a spring controlled operating arm or lever 46 disposed on the exterior of the box ll in the path of travel of one of the lower bucket guide rollers d? which are rotatably mounted on opposite sides of the lower rear portion of the bucket ll. The bucket 17 is also provided with upper guide rollers 48.

The bucket guide rollers ll and 3'8 are positioned on opposite sides of the bucket H and travel in guide tracks 49 and auxiliary tracks 50 which are formed on the loading frame uprights 9 by angle irons 5i and side plates 52 secured to the channel uprights.

The auxiliary guide tracks 50 are located near the upper portion of the loading frame and are adapted to serve as guides for the lower bucket rollers 41 when the upper rollers 48 reached the upper closed and curved ends of the main guide tracks 49 to cause the hoisted loading bucket, at the upper limit of its travel, to be upset or tilted to discharge a batch of material into the chute l of the mixer, as illustrated in dotted lines in Figure 1 in which the flop gate 2| is moved into open position by the discharging stream of the material.

The loading bucket I1 is operated by cables 53 adapted to be wound and unwound on drums or reels 54 mounted on the auxiliary framework I I and operated by a three phase motor 55 having terminals T-l, T-2 and T-3 to which circuit lines Ll, L2 and L3 are respectively connected, as shown in Figure 7. The motor 55 acts through a speed reducer drive 51 to drive the belt 56 which operates the cable drum shaft and the drums mounted thereon. The motor 55. has a solenoid brake 58 connected across the terminals T?! and T..2 thereof.

The motor is connected with the reversing unit I 3 and with the switch button motor control box 14 containin a main bucket hoisting control switch 59, a bucket stop switch 60 and a main bucket lowering control switch 6|. The motor stop switch 60 is connected by a wire 62 to the line wire 1H3 and by a wire 63 to one terminal of the raise switch 59 as shown in the wirin diagram of Figure 7. A wire 64 connects the hoisting switch 58 to a terminal of the main bucket lowering switch 6!. A wire 65 connects the second terminal of the bucket lowering switch 61 to the terminal 44 in the bucket lowering control switch box 4!. A wire '66 connects the terminal v43 in the switch box 4| to one terminal of a magnetic coil 61, the other terminal of which has a wire 68 connected thereto. The wire 68 is also connected to the line wire L-l. Connected to the second terminal of the main hoist control switch 59 is one end of a wire 69 the other end being connected to one terminal of an auxiliary bucket hoist or raise switch 10. The second terminal of the auxiliary hoist control switch lii is connected by a wire H to one terminal of a magnetic coil 12 having a wire 13 connecting the same to the line wire Ll.

The auxiliary hoist control switch 10 is mounted in a bucket hoisting control box 12 which is secured on the upper portion of the loading framework upright 9 on which the box 4| is mounted. The auxiliary hoist control switch Ill is operable by means of a spring controlled arm or lever 13 mounted on the'exterior of the upper switch box 72 in the path of travel of one of the lower bucket rollers 47 to be operated thereby at the upper limit of movement of the bucket t cause opening of the auxiliary hoist control switch is to break the bucket hoisting circuit to stop the bucket hoisting motor 55, permitting discharge of the pre-cleaned batch of material into the mixer.

As shown in the wiring diagram of Figure '7 the vibrator control terminal 42, in the switch box 4| is connected to the line wire L3 by a wire 14. The vibrator control terminal 39, in the box 4|, is connected to the line wire L2 by a wire 15a.

The loading bucket I1 is equipped with, the vibratory screen 2'3, so that when the bucket is in its lower position spent and inert material, such as previously used foundry sand, is shoveled or otherwise deposited on the screen 23 which is vibrated by the vibrator 24 when the vibrator control switches 29 and 30 are closed and the auxiliary control switch 45 is in contact with the terminals 40 and 42. Vibration of the screen causes removal of the coarse metallic material and foreign matter which slides down or is shimmied oif of the screen, while the sand grains and finer material and dust sift and fiow through the screen and into the bucket.

For the purposes of exhausting or withdrawing the fines from the materials which enters the bucket an'air exhaust mechanism is provided for coaction with the bucket when in its lower loading position. The back wall of the bucket is provided with the exhaust opening or outlet port 20 (Figure 3) which, in the lowered position of the bucket registers with the mouth 75 of an air exhaust or suction box 16. Secured around the mouth 15 of the air exhaust box 16 is a resilient packing or sealing frame 17 constructed of a strip of rubber or the like folded upon itself to form a flexible bead against which the back of the bucket, when lowered, is adapted to be brought into air sealing contact as shown in Figure 3. Connected to one end of the air exhaust box 16 is one end of an air exhaust pipe or flue 18, the other end of which is connected to a dry-type air exhauster l9 operable by a motor 80 connected to the air exhaust control box I and the push button control box IS. The operation of the air exhaust is controlled by the start and stop buttons in the box l6.

With the bucket H, in its lowered position (Figure 1) and having the back thereof in sealing contact with the air exhaust sealing frame 11 of the air exhaust box 16, the air exhaust start button is pushed thereby causing air to be sucked or drawn through the screen and the upper port of the bucket and then through the bucket spout or chute I9 to exhaust through the exhauster 19. As material is shoveled into the bucket the finer particles and the fines pass through the screen 23 into the bucket, but the material flow is intercepted by the air exhaust currents which pass through the material stream, thereby causing the dust and fines to be separated from the material grains which drop into the bucket to load the same simultaneous with the exhaust and discharge of the dust and fines through-the exhauster 19. It will thus be noted that an improved method of loading spent foundry sand and the like is adapted to be practiced with the bucket loading equipment herein described, whereby the material has the coarse and foreign matter removed therefrom and discharged, simultaneous with the screening and the suction removal of the fines allOWing the bucket to be loaded only with the pre-cleaned material which is to be batch fed by the loading unit into the mixer to be treated, bonded and 11eclaimed for reuse.

When the bucket H has been loaded, as described, the operator presses the main hoisting switch control button thereby closing the main switch 59 to establish the bucket hoisting or raising circuit through the motor 55 to cause winding up of the cables 53 to raise the bucket from the'full line position of Figure 1 into the dotted line discharge position. As the upper bucket rollers 43 reach the main guide tracks 49 the lower bucket rollers G'i pass into the auxiliary tracks 56 thereby gradually upsetting or inverting the loaded bucket. When the lower rollers a! approach their upper limits one of the rollers t? engages the spring controlled lever 13 to swing the same upwardly thereby opening the auxiliary hoist control switch 59 to break the circuit to the motor 55 and thereby stop the bucket permitting the loaded bucket to discharge a batch of the pro-cleaned material through the bucket discharge chute [9 into the mixer receiving chute 'l beneath the opened bucket flop gate 2|.

At the beginning of the bucket hoisting operation, the upward movement of the bucket raises the vibrator control switch box 28 thereby opening the vibrator control switch to stop the vibrator and simultaneously release the spring controlled lower limit switch lever Q6 permitting the control switch 45 to break contact with the terminals t8 and G2 and establish contact with the terminals 43 and 44.

After the bucket has been unloaded in its uppermost inverted position as shown in dotted lines in Figure 1, the operator merely pushes the the closed upper ends of switch control button 6| to close the main bucket lowering control switch thereby establishing the bucket lowering circuit to the motor 55, causing reversal thereof to unwind the cables 53 permitting release of the upper control lever '23 and closing of the auxiliary hoist control switch 10 ready for the next bucket hoisting operation.

The stop switch 60 is common to both the bucket raising and lowering control circuits, so that in case it is desired to stop the travel of the bucket in a selected position, it is only necessary for the operator to press the button of the stop switch 65 to open the switch and thereby stop the motor 5'5.

The bucket control main hoisting switch 5-9 and main lowering control switch Bl are so mounted that when one switch is closed the other one is opened.

The air exhauster is controlled by the operation of the start and stop buttons provided in the switch an IE. During the operation of the bucket loading mechanism the air exhauster may be started in any position of the bucket and may be left operating during a series of bucket loading and emptying operations. If desired the exhauster may be set in operation at the beginning of a bucket loading operation and then stopped when the bucket is hoisted for delivering a charge to the mixer.

It is to be understood, that the machine herein described may be employed in small establishments as well as in large ones, for the purpose of screening and removing fines from materials in a loading bucket to permit a partially cleaned material to be delivered to a material treating or reclaiming apparatus and thus obviating the necessity of removing the fines after the material is delivered to the apparatus.

lhe various steps in the combination loading, screening, fines removal and treating of spent or inert materials such as foundry sand and the like, may be separately and independently timed, by an attendant by a manual operation of the respective push button control boxes mounted on the control panel of the machine assembly, thereby providing a simple, effective and economical material reclaiming and treating system.

While a selected machine assembly or system has been illustrated and described for practicing the method of bucket cleaning and fines removal of materials prior to the reclaiming of the materials in material receiving units, it is to be understood that the machine assembly is one exemplification of the principles involved. The right is accordingly reserved to make such changes in the construction and in the arrangement and combination of the elements and parts .of the system as will widen the field of utility and increase the adaptability of the system without' departing from the principles of this invention. It is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

We claim as our invention:

1. In a material reclaiming system wherein a material treating machine is adapted to receive and recondition spent materials, said system including'a loading device comprising a loading bucket mounted for movement in the framework, means for operating the bucket for delivering material to the machine, means on the bucket for screening the material as it enters the bucket,

and means for withdrawing fines from the material receiving and treating machine is adapted to receive and recondition spent materials, a loading device comprising a framework mounted adjacent the machine, a, loading bucket operable in the framework, means for raising and lowering the bucket for delivering material to the machine, a screen mechanism mounted on the bucket for screening the material as it enters the bucket, and suction means for drawing air through the material entering the bucket to extract dust and fines from the material prior to delivery to the machine.

3. A material loader comprising a framework, a bucket operable therein, means i or lowering nd hoisting the bucket to move the same into receiv ing and discharging positions, a screen on the bucket for removing coarse matter therefrom and permitting finer material to drop into the bucket, a vibrator for vibrating the screen with the bucket in a material receiving position, nd a vibrator control governed by the movement of the bucket into and out of receiving position.

4. A material loader comprising a framework, a loading bucket operable therein, means for moving the bucket into receiving and discharging positions in the framework, a screen on the bucket for removing coarse matter from material antering the bucket, a vibrator for operating the screen, a control for starting and stopping the vibrator as the bucket moves into and out of material receiving position, and means coacting with the bucket when in receiving position for exhausting air current through the bucket and through the material entering the same to exhaust dust and fines from the material while the bucket is being loaded.

5. A bucket loader mechanism comprising a framework, bucket guides on the framework, a loading bucket in the framework, means for hoisting and lowering the bucket in a predetermined course prescribed by th bucket guides, a screen on the bucket for removin coarse matter from material as it is delivered into the bucket, a vibrator for vibrating the screen, and control switch members mounted on the bucket and on the framework adapted to be moved into and out of coacting relationship to govern the starting and stopping of the vibrator as the bucket moves into and out of receiving position on the framework.

6. A bucket loader mechanism comprising a framework, bucket guides on the framework, a loading bucket in the framework, means for hoisting and lowering the bucket in a predetermined course prescribed by the bucket guides, a. screen on the bucket for removing coarse matter from material as it is delivered into the bucket, a vibrator for vibrating the screen, control switch members mounted on the bucket and on the framework adapted to be moved into and out of coacting relationship to govern the starting and stopping of the vibrator as the bucket moves into and out of receiving position on the framework, and an air exhaust mechanism positioned for action with the bucket when in loading position to draw air currents through the bucket and through the stream of material entering the bucket to remove fines from the material While being loaded.

7. A material loading mechanism comprising a framework, loading bucket operable therein, means for hoisting and lowering the bucket to move the same from a loading to a discharging position, a screen on the bucket'for removing coarse and foreign matter from material delivered to the bucket, a vibrator connected with the 10 screen, a, vibrator control switch mechanism carried by the bucket, and electric contacts supported on the framework to be engaged and disengaged by the switch mechanism to govern the operation of the vibrator and the screen as the bucket moves into and out of loading position.

8. A material loading mechanism comprising a framework, a loading bucket operable therein, means for hoisting and lowering the bucket to alternately move the same from a loading to a discharging position, said bucket having a material receiving opening and an air exhaust opening therein, a suction box mounted on the framework, and having an air exhaust opening therein, a resilient sealing frame on the suction box around the air exhaust opening thereof to form a sealing contact around the exhaust opening of the bucket when the bucket is in a loading position, and an air exhaust mechanism connected with the suction box to cause air currents to be drawn through the suction box across the stream of material entering the bucket to exhaust fines from the material while the bucket is being loaded.

9. The combination with a material loading bucket, of means for moving the same into and out of material receiving position, an air exhaust mechanism positioned to coact with the bucket when the same is in a material receiving position to cause air :current to be drawn through the stream of entering material to exhaust fines therefrom, and a friction seal between the air exhaust mechanism and the bucket.

10. The combination with a material loading bucket, of an air exhaust mechanism for drawing air currents through the bucket across the stream of entering material to exhaust fines therefrom, an air seal on the air exhaust mechanism for flexible sealing contact with the bucket when in loading position, and control means connected with the air exhaust mechanism to start and stop the same.

11. A material loading mechanism comprising a framework having bucket guide tr'acks formed thereon, a loading bucket positioned for movement in the guide tracks alternately from a loading to a discharging position, means for hoisting and lowering the bucket, a push button control for governing the hoisting and lowering of the bucket, an auxiliary hoist control switch mechanism operable by the bucket when moving into discharge position, a combination vibrator and bucket lowering auxiliary control switch mechanism mounted on the framework and operable by the bucket when moving into its loading position, a screen mechanism on the bucket, a vibrator connected therewith for operating the same, and a vibrator control switch mechanism on the framework and on the bucket for coaction with the combination vibrator and the bucket lowering auxiliary control switch for governing the raising and lowering of the bucket and the automatic control of the vibrator.

12. A material loading mechanism comprising a framework having bucket guides formed thereon, a bucket positioned to move in said guides into loading and discharging positions, means for raising and lowering the bucket, a main control connected with'said means for governing the operation thereof, an auxiliaryhoisting control connected with the main control and operable by the bucket, a screening mechanism on the bucket, and a combination auxiliary bucket lowering control and a screen operating control connected with the main control and with the screen mechanism and governed by the movement of the bucket into and out of loading position.

13. A material loading mechanism comprising a framework, a loading bucket operable in the framework, means for operating the bucket, a main control for said means, a material screen on said bucket, a vibrator for vibrating the same, switch control mechanisms on the framework and on the bucket connected with the main control and operable by the movement of the bucket into and out of loading position for starting and stopping the operation of the vibrator.

14. A material loading mechanism comprising a framework, a loading bucket operable in the framework, means for operating the bucket, a main control for said means, a material screen on said bucket, a vibrator for vibrating the same, switch control mechanisms on the framework and on the bucket connected with the main control and operable by the movement of the bucket into and out of loading position for starting and stopping the operation of the vibrator, and means cooperating with the bucket when in loading position for, withdrawing fines from the material after passing through the screen and on entering the bucket.

15. A material loading mechanism comprising a framework, a loading bucket operable in the framework, means for operating the bucket, a main control for said means, a material screen on said bucket, a vibrator for vibrating the same, switch control mechanisms on the framework and on the bucket connected with the main control and operable by the movement of the bucket into and out of loading position for starting and stopping the operation of the vibrator, and a switch controlled suction mechanism positioned to coact with the bucket when in loading osition to draw 'air current through the screen and through the stream of material entering the bucket to remove fines from the material.

16. A material loading mechanism comprising a framework, a loading bucket operable therein, means for operating the bucket in the framework, a main control for said means, auxiliary controls on the framework connected with the main control and operable by the movement of the bucket, a material screening mechanism on the bucket, and a screening mechanism control switch connected with one of the auxiliary controls and operable by the movement of the bucket into and out of loading position to govern the operation of the screening mechanism.

AXEL G. GRANATH.

JULIUS J. GRUENFELD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

